Weatherproof electric winding



H. H'. WERMENE MBATHBRBROOF ELECTRIC :WINDI'NG aEil ed July 16, r1928 32 vSheets-Shoat. .1

Jqnelo, 1930. WERMINE 1,763,115

wBATnERPRooF ELECTRIC WINDING Filed July 16, 1928 2 Sheets-Sheet 2 ZZZ/0W: H. WWWLH/Z Patented June 10, 1930 UNITED STATES PAT'ENT- OFFICE 01' VILLA rm,'n.r.mo1s, ASBIGNOB 'IO BELDEN MANUFAC- TURING comm, OF CHICAGO, ILLINOIS, A' CORPORATION OI ILLINOIS WEA'IEEBPBOOF ELECTRIC WINDING Application filed July 18, 1928. Serial No. 293,071.

the same time serve as a hermetic seal forthe winding, thereby protecting the latter a ainst moisture or other deleterious agencies w lnch might otherwise afiect the efliciency or durability of the winding.

1 Further objects of the invention are to provide a casing which may be employed as a support or mountin for the electric unit; to provide a casing w ich, besides protecting the coil from climatic conditions, will at the same so time protect the coil from mechanical abuse or injury due to rough handling; to provide a unitary structure which shall be of a well finished, ornamental and neat appearance while being relatively compact in size; to pro- 25 vide a construction which maybe rapidly and economically manufactured, and to provide an improved method or process for making the described structure, and, in general, to provide an im roved, efficient and economical ao structure an method of the character referred to.

In certain of it's as ects, the invention may be'considered as a mo 'fication of or improvement on the invention disclosed in my pendinggzplication Serial No. 180,356, filed April In the drawings, I have illustrated the in vention as applied to a radio transformer of the audio type, and in said drawin Fi 1 represents a erspective o the finishe transformer wit in its weather-proof casing.

Fig. 2 is a perspective view of the bobbin and terminals. Y

Fig. 3 is a plan view of one end of the bobbin illustrated in Fig. 2, and showing how the terminals are connected to the windings.

Fig. 4 is a side elevation of the bobbin windand laminated core after assembly.

{Sis a perspective view of one part of the tw0-part shield which encloses the active elements of the structure.

Fig. .6 is a perspective view of the transformer enclosed in its shield, portions of the latterbeing broken away.

Fig. 7 is a sectional view of the preliminary mod, showing the first molding operation, an

Fig. 8 is a vertical section through the mold showing. the final molding operation.

Referring to the drawings, it will be observed that the bobbin, which as a whole may be desi ated 10, comprises a barrel 11 and a pair 0 heads or circumferential flanges 12 and13. The barrel is made with a square or rectangular aperture to accommodate the laminations, and the heads 12 and 13 are each made with an inside step, as shown at 14, in order to provide a proper support for the mlca wrapper extending around the low tension or primary winding 16. The width of said flange 14 is made suflicient to insure a proper la ping of the mica wrapper 15 at its ends so t at the high tension winding 17 which fills the outer space of the bobbin will not haveany tendency to slip down into contact with the inner or low tension windin Said high tension winding 17' on its outside surface is protected andinsulated by the mica wrapping 18, which, if desired 'may lap over and be supported bythe outer anrfaces of the flanges 12 and 13 of the bob- In order to facilitate the bringing out of the ends of the primar and secondary wind. ings of the coil, I re er to rigidly secure to one end of the bob in a set of four relatively stifi" conductor pins or terminals 19. The inner ends of these conductor pins 19 are hooked as shown at 20 and embedded in small oval-shaped blocks 21 which are formed as integral parts of the head 13 of the spool- 10. Preferably, the entire s 001, consisting of the barrel 11. heads 12 an 13, and anchor blocks 21, is formed of material such as bakelite and is molded as a one-piece unitary tor pins 19 .are left exposed, as well shownin Figures 2 and 6 of the drawings, so that the wires, as, for example, 22, which lead through apertures 23 in the spool head 13, may be connected to the inner ends 20 of said terminal pins by soldering, as shown, or in any other suitable manner.

After the spool has been equipped with its low tension and high tension windings and suitably insulated, the laminations are inserted. Preferably, these laminations are of the usual mating T and U shape, as shown at 24 and 25 in Figure 4 of the drawings. Also, after the assembly of the laminations has been completed, the fiber sheet 26 is wrapped around the edges of the laminations to insulate the edges of the same from the inner wall of a metallic, preferably steel, shield which includes the winding and laminations. This shield preferably comprises a pair of like parts, one of which, 27, is illustrated in perspective'in Figure 5. As shown. best in Fi res 5 and 6, the shield parts are provi ed with a pair of apertures 28 of sufiicient diameter to avoid contact with the conducing pins 19 which pass through said apertures. Also, to one of the parts 27 "of the metal shield, there is secured a grounding pin 29, preferably by solderin or welding to the side of the shleld, as in lcated at 30.

The parts constructed as above described and assembled in the condition shown in Figure 6, are now in condition to be sup-1 plle'd with the weather-proof casing which constitutes an important feature of the in-.

vention. Such casing is made of bakelite or analogous material capable of being molded and made hard by the application of pressure and heat. Since in the .molding of such material very heavy pressure is required, usually at least one thousand pounds per square inch, it is desirable, if not essential, to prevent injury to the relatively delicate coils with which transformers of the type here described are frequently wound. In the present instance, this protection of the windings against the pressure incident to the molding operation is effected in different ways. In the first place, I provide the shield composed of the mating sheet metal parts 27 which closely abut together to effect a seal at the seam line 31 of the shield as a. whole; and also it will be observed that where the terminal pins 19 extend through the shelf portion 32 of the steel shield, the said shelf portion 32 rests directly in contact with and upon the upper flat surface of the block 21, so that the bakelite cannot flow into the interior of the structure through the said apertures 28, which, as previousl stated, are considerably larger in diameter t an the pins 29 in order to avoid short circuits.

urthermore, where the shield parts 27 are m de of relatively light auge metal for obvious reasons, so that t ey might possibly collapse under the pressure 'of the molding operation if subjected to heav side pressure of the order indicated, this di culty is avoided by applyin the major part of the molding ressure in a irection parallel with the lammations, so that the laminations of the coil structure and also the spool of the coil itself serve in a measure to resist the mold pressure and prevent distortion or collapsing of the structure with resulting damage to the electrical windings.

Also, in order still further to facilitate the molding of the casing without inconvenience and without damage to the structure, I prefer to effect the moldin in two operations, which will now be descri ed.

In Fig. f the drawings, I have illustrated the cavity member. 33 of the mold or die which is used in the preliminary as well as in the final molding operation. Inthe preliminary molding operation, the portion 33 of the mold is used in connection with a temporary plunger 34 or punch which is of proper dimensions so that the opening or recess formed b said punch will permit insertion of the shlelded transformer into said cavity in the osition as indicated in Fig. 8.

In the first or preliminary v molding operation, the cavity of the mold portion 33 is char ed with the proper amount of owdered bake ite or bakelized material and t e plunger 34 is brought down in the usual way withressure and heat applied so that there is ormed in the recess of the mold portion 33 a semi-cured, open topped. shell or receptacle 35, said shell or receptacle, as above stated, being of the roper internal dimensions to permit the shielded transformer to be lowered or inserted therein.

After thepreformin plunger 34 has been removed and the shielded transformer substituted therefor, as indicated in Fig. 8 of the drawings, a further supply of the bakelite powder is introduced into the top of the cavity of mold portion 33 and over the up per end and the terminals of the transformer, after which the final plunger or die portion 36 is brought down into the position shown in Fig. 8 and heat and pressure applied in the usual manner. It will be observed that the upper die portion 36 of the mold is fitted with a set of bushings as shown at 37, each of said bushings having at its lower end a conical recess 38 opening into a vertically extending bore 39, the uppenend of which is of somewhat greater diameter than the lower end, which lower end substantially fits one of the pins 19 or 29 and registers therewith.

The finished article resulting from the sec- .ond or final molding operation is illustrated If desired, perforated washers as indicated at 40 in Fig. 8, may be fitted over the four means-any kind of terminal pins ,19 to prevent possible leakage of bakelite into the interior of the shield.

The term bakelite, as used in the claims, henolic condensation product, or the like, w ich is capable of being hardened by heat and pressure.

I am aware that changes may be made in the structure and method of making the same above described without departing from the spirit of my invention, the scope of which s ould be determined by reference to the following claims, the same being construed as broadly as possible consistent with the state of the art.

I claim as my invention:

1. The method of applying a weatherproof casing to an electric winding which consists in first molding an open-ended shell, then inserting the winding into said shell, and then molding a cover over said open end to comsletely enclose said winding while consoliating said cover material with the material of the premolded shell.

2, The method of applying a bakelite casing to an electric winding which consists in first molding anopen-ended shell of partially cured bakelite material, then inserting the winding into said shell, and then molding a cover over said open end to completely enclose said winding while applying heat and pressure to consolidate said cover material with'the material of the'premolded shell.

3. The method of ap lying a bakelite casing to an electric win ing with projecting terminals which consists in first molding an open-ended shell of partially cured bakelite material, then inserting the winding into said shell, and then molding a cover over said open end to completely enclose said winding while applying heat and pressure to consolidlate said cover material with the material of t e pro ecting outwardly through the casing.

uly 13, 1928.

HUGO H. WERMINE.

premolded shell and to seal the terminals 

